By OCs, we are talking people that have their own fursonas right, and not canon characters?
A lot of my friends are easily folks I could crush on if I'm honest! Especially if we're talking generally, knowing it's not specifically a vore or paw/feet related question.

My boyfriend's OC Phyre gets an obvious mention, but is also my cheating option haha.
Among other friends though, Mukiro is the first that came to mind, easily a crush, both somali cat and human forms!
RaccoonVandal's Ruka and Kozu are easy picks too that I swoon for!
LowenMothbat's Rowan, Kohen and Forest are my faves (though Lowen has so many to choose from!!)
Fish and Deocks have themselves too, I'm surprised we haven't done more together with the three of us!
Ipipo and Labbeh not only being good friends are also big oc crushes of mine, not to mention the plethora of characters both guys have additionally to their mains!
FeetyMcFoot's Leo is an easy crush, also as is MegaSonic's King Anthony and Apollo~
Given they're my pets, I'd be terrible to not mention Crash and Daxon too x3
I have many more friends with many crushable OCs but these are among some that came to mind for right now.